Method of locating nas context

ABSTRACT

A method of locating NAS context relating to a network access server session in a communication network is provided, the method comprising receiving an Accounting Stop Request for a PDP context associated to a network access server session, comparing an Accounting Session ID implemented in the Accounting Stop Request with Accounting Session IDs associated with active network access server sessions, in case that no matching Accounting Session ID is found, determining whether a value of an identification parameter implemented in the received Accounting Stop Request matches a value of a corresponding identification parameter associated with an active network access server session, and locating a NAS context based on the result of matching identification parameters.

FIELD OF INVENTION

The present invention relates to a method of locating NAS context, inparticular to a method of locating NAS context based on anAccounting-Request Stop message without using an Accounting Session ID.Furthermore, the invention relates to a program element, and acomputer-readable medium.

ART BACKGROUND

In a Public Land Mobile Network (PLMN), a Service Aware (SA) node suchas the so-called Flexi ISN can be deployed behind a Gateway GPRS SupportNode (GGSN), corresponding to a so-called Gi-deployment, to enableoperators to offer services in a more flexible and efficient way. Thecommunication between GGSN and SA node is performed through the NetworkAccess Server (NAS) interface. NAS interface uses Radius AuthenticationDial In User Service (RADIUS) authentication for allocating the IPaddress (if needed) and RADIUS accounting for providing the IP address,International Mobile Subscriber Identity (IMSI) and Mobile SubscriberISDN (MSISDN) to the SA node. The NAS can be for example a 3rd partyGGSN that acts as a RADIUS client and a SA node that acts as a RADIUSserver. The user plane traffic is carried in plain IP, Generic RoutingEncapsulation (GRE) or IP-in-IP tunnels and the RADIUS signalling isused to set up the user plane traffic in a similar way as in the GPRS/3Gnetworks. The NAS interface can be referred to as being the southboundGi interface, as an alternative to the Gn interface.

During the Public Data Network (PDP) Context activation procedure, an“Accounting-Request-START” message, including an Access Point Name(APN), is sent from GGSN towards the SA node to inform it about thesubscriber identification (IMSI, MSISDN) so that user profile can bedetermined. Upon receiving of the message a NAS context is established.Thus, the START message is used to inform SA node about new sessions, sothat SA node can monitor them properly. An “Accounting-Request-STOP”message can be used by GGSN to inform the SA node about a possible PDPContext termination, thus SA has to delete the already established NASContext.

RADIUS Accounting-Request-Start and Stop messages may be used duringboth primary and secondary PDP context activation and deactivationprocedures, respectively. If the SA node is used for IP addressassignment, then, upon reception of a RADIUS “Accounting-Request-STOP”message for all PDP Contexts associated to a session, the SA node(server) may make the associated IP address available for assignment.

In order to avoid race conditions, the GGSN shall include a 3GPPVendor-Specific sub-attribute Session Stop indicator when it sends the“Accounting-Request STOP” for the last PDP context of a PDP session andthe PDP session is terminated (i.e. the IP address and all GTP tunnelscan be released). The SA server shall not assume the PDP sessionterminated until an “Accounting-Request STOP” with the Session StopIndicator is received. In 3GPP reference architecture, the SA functioncorresponds to Flow Based Charging (FBC), which is implemented inRelease 6 TPF (Traffic Plane Function) and in Release 7 PCEF (Policy andCharging Enforcement Function). 3GPP does not define interface betweenGGSN and TPF/PCEF. SA function can be integrated as part of GGSN or itcan be implemented separate node connected to GGSN via Gi interfacedefined in 3GPP specification 29.061, which corresponds to the NASinterface described above.

Even though 3GPP reference architecture does not specify details aboutthe case where GGSN and TPF/PCEF are implemented as separate nodes, thisalternative is often used in practice. For operators, this approach hasthe benefit that SA can be introduced without making changes to existingGGSN nodes.

However, there may be a need for a method of locating an NAS context,which improved performance; in particular, with respect to a morereliable or fail-proof locating of the NAS context in order to enable animproved release of the IP address and/or all GTP tunnels.

SUMMARY OF THE INVENTION

This need may be met by a method of locating NAS context, a programelement, and a computer-readable medium according to the independentclaims. Advantageous embodiments of the present invention are describedby the dependent claims.

According to an exemplary aspect a method of locating NAS contextrelating to a network access server session in a communication networkis provided, the method comprising receiving an Accounting Stop Requestfor a PDP context associated to a network access server session,comparing an Accounting Session ID implemented in the Accounting StopRequest with Accounting Session IDs associated with active networkaccess server sessions, in case that no matching Accounting Session IDis found, determining whether a value of an identification parameterimplemented in the received Accounting Stop Request matches a value of acorresponding identification parameter associated with an active networkaccess server session, and locating a NAS context based on the result ofmatching identification parameters.

In particular, the Accounting Stop Request may be a RADIUS AccountingStop Request. Furthermore, the Accounting Stop Request may be sent froma GGSN. The GGSN may operate according to the 3GPP protocol. Inparticular, the timer may be configurable by an operator, e.g. of theNAS. Furthermore, a method according to an exemplary aspect of theinvention may be performed by a device, e.g. a network access server,which is adapted to perform the above mentioned method. Such a devicemay also be part of the present invention.

In particular, the Accounting Stop Request may be received by a networkaccess server, which may also be used to perform the method.Furthermore, in case a matching identification parameter is found therelated NAS context of the associated network access server session maybe identified as the NAS context to be located. The locating of the NAScontext may be in particular an identifying of the respective NAScontext. In particular, the network access server may search several orall of its active network access server sessions and compare several orall of the respective identification parameters which may be useful orsuitable to identify that network access server sessions which isaddressed by the Accounting Stop Request.

According to an exemplary aspect of the invention a program element isprovided, which, when being executed by a processor, is adapted tocontrol or carry out a method according to an exemplary aspect of theinvention.

According to an exemplary aspect of the invention a computer-readablemedium is provided, in which a computer program is stored which, whenbeing executed by a processor, is adapted to control or carry out amethod according to an exemplary aspect of the invention.

The term “network access server session” may particularly denote asession for which a “network access server (NAS) context” may beestablished when an Accounting-Request-Start or accounting start requestis sent from a gateway, e.g. a GGSN toward a service aware (SA) node toinform the SA node about subscriber identification (IMSI, MSISDN) sothat a user profile may be determined. However, a new NAS context maynot always be created when Accounting-Request-Start is received. A newNAS context may only be created if Accounting-Request-Start is about anew PDP session, i.e. received tuple (IMSI, MSISDN, IP address, APN) isunique. If Accounting-Request-Start is about existing PDP session andthus related to some existing NAS context in SA node, then theAccounting Session ID may be recorded to this NAS context (if AccountingSession ID is received in the message). In general there may be aone-to-one relation between PDP session and NAS context, i.e. NAScontext can be single primary PDP context or NAS context is a set ofsecondary PDP contexts belonging to the same PDP session. When PDPsession contains more than one PDP context, all those PDP contexts maybe called secondary PDP contexts and if PDP session contains one PDPcontext, this PDP context may be called primary PDP context.

That is, a NAS context may be established at the beginning of a newsession, service or communication relating to a new PDP session and maybe used in order to identify the specific PDP session.

By providing a method according to an exemplary aspect of the inventionit may be possible to ensure that, in case an SA does receive anAccounting-Request-Stop message relating to an Accounting-Request-Startmessage which was never received or processed by that node, no datapackets are wrongly dropped. For example, GGSN may be compliant with3GPP Specs and there is some remaining PDP contexts in the PDP sessionthat SA node is not aware.

That is, by comparing values of identification parameters it may bepossible to determine the network access server session the receivedAccounting Stop Request corresponds to even in cases when the AccountingSession ID is not known to the side receiving the Accounting StopRequest, e.g. a network access server. That may be the case when thereceiving side did not receive or did not process an initiallytransmitted accounting start request, into which usually the AccountingSession ID is implemented. The result of this determining or checkingmay indicate whether an existing network access server context is foundor not. In particular, it may be possible to avoid that a Service Aware(SA) node may start dropping all the user plane packets related toremaining PDP context(s) in the sending GGSN and may ignore accountingstop/interim messages related to those PDP(s).

A gist of an exemplary aspect of the invention may be that in case noAccounting Session ID is implemented in an Accounting Stop Requestreceived by a network access server or no matching Accounting Session IDis found in the network access server, the network access serversearches other identification parameters which may be used in order toverify the NAS context or PDP context the respective Accounting StopRequest belongs to. In particular, the network access server may performa search for a matching NAS context involving several or all NAScontexts active on that network access server. Thus, even in cases thatno Accounting Session ID is sent it may be possible to determine orlocate the corresponding NAS context on the network access server sothat the respective NAS context may be deactivated to enable a releaseof the respective resource in appropriate cases.

Next, further exemplary embodiments of the method are described.However, these embodiments also apply to the, the program element, andthe computer-readable medium.

According to another exemplary embodiment of the method theidentification parameter is one of the group consisting of: an IPaddress, an Access Point Name, an International Mobile SubscriberIdentity, and Mobile Subscriber ISDN (MSISDN). All these parameters maybe suitable parameters in order to locate or identify NAS contextrelating or associated with the received Accounting-Request-Stopmessage.

According to another exemplary embodiment of the method the located NAScontext corresponds to the NAS context having a related network accessserver session to which a matching value of an identification parameteris associated.

According to another exemplary embodiment of the method the located NAScontext in case it is determined that a Session Stop Indicator isincluded in the Accounting Stop Request.

By deactivating the located NAS context the related network accessserver session may also be deactivated. Thus, the respective resourcemay be released.

According to another exemplary embodiment of the method the AccountingStop Request is ignored in case it is determined that a Session StopIndicator is not included in the Accounting Stop Request.

According to another exemplary embodiment the method further comprises,in case that a matching Accounting Session ID is found, deciding whethera Session Stop Indicator is included in the Accounting Stop Request, incase no Session Stop Indicator is included deciding whether further PDPcontexts are associated with the network access server session, and incase no further PDP context is associated with the network access serversession, starting an IDLE Timer to determine a point in time forreleasing the communication resources.

The term “communication resource” may particularly denote or relate toan IP address, an International Mobile Subscriber Identity, or a MobileSubscriber ISDN, for example, which may be allocated to a specificcommunication in case a request for a communication or data transfer issent, e.g. by using so-called RADIUS authentication and/or RADIUSaccounting.

By providing a method according to this exemplary embodiment it may bepossible to ensure that resources are released earlier than in the caseof known methods. In particular, the method may provide a procedure tohandle cases in which no Session Stop Indicators or Session StopIndicator attributes are sent together with the Accounting Stop Request.This may in particular happen, in cases where the GGSN, which sends theAccounting Stop Request, is not compliant with latest 3GPP Specs whereusage of Session Stop Indicator attribute is defined. In other words, inthese cases a Session Stop Indicator attribute may not sent even if an“Accounting Request STOP” message, e.g. a RADIUS Accounting StopRequest, is about the last PDP context of the PDP session. In suchfaulty cases, according to the known procedures, NAS context may not bereleased—if one follows pedantically 3GPP specifications—and thusresources are wasted. This wasting of resources may be reduced whenusing a method according to an exemplary aspect of the invention.

Although, problems arising from the use of GGSN which are not compliantwith the 3GPP specification, could be fixed at the GGSN and not at thereceiving side, e.g. a receiver of a RADIUS requests, it may beadvantageous to take care of at least some of the problems at thereceiving side, since this may improve the flexibility of the used GGSNnode. For example, it may not be necessary to make any changes to legacyGGSN and/or it may be possible to send Session Stop Indicator only if acertain (RADIUS) accounting mode is selected, and this (RADIUS)accounting mode cannot be enabled unless operator has bought the relatedsoftware sales item.

According to another exemplary embodiment of the method thedetermination of the point in time is based on a predetermined timeinterval, wherein the predetermined time interval is measured from thestarting of the IDLE Timer. In particular, the predetermined timeinterval may be in the range of a few minutes, e.g. the time intervalmay be less than 15 minutes or less than 10 minutes or less than 5minutes.

Furthermore, it should be noted that the IDLE Timer according to thisexemplary embodiments of the invention is not the same idle timer, whichmay be used in general to terminate idle bearer sessions in GGSN or SAnode according to commonly known methods. Typical value for general idletimer can be several hours, while the IDLE Timer used in exemplaryembodiments of this invention would typically have configured value asonly a few minutes. If user plane traffic is detected before IDLE Timerexpires then SA node knows that there is active (but yet unknown) PDPcontext related to NAS context and it may start using general idle timerto detect inactivity in the NAS context. Thus, the IDLE Timer accordingto exemplary embodiments of the invention may be formed as anadditionally IDLE Timer which may precede the commonly known idle timer.

Even if usage of IDLE timer may mean that detection of the terminatedPDP session may happen later than it actually occurred, the SA node mayuse the correct termination time when it is informing other nodes aboutthe terminated NAS context. Event-Timestamp attribute may be used inRADIUS and Diameter requests originated from the SA node to indicate theright time when the NAS context was terminated and Change Timeinformation element in CDR may be used for same purpose in offlinecharging interface.

According to another exemplary embodiment the method further comprises,in case the IDLE Timer is started, checking whether furthercommunication associated to the network access server session isperformed in the communication network.

According to another exemplary embodiment the method further comprises,in case no further communication is performed till the determined pointin time is reached, deactivating the network access server session. Inparticular, the deactivating may be performed by deactivating a NAScontext which is associated with or established for the network accessserver session.

According to another exemplary embodiment the method further comprisesremoving the Accounting Session ID from the network access servercontext associated with the network access server session, in case noAccounting Session ID is included. In particular, the Accounting SessionID may be included in the Accounting Stop Request and/or may be known tothe receiving NAS.

Summarizing an exemplary aspect of the invention may be seen inproviding a way to detect in TPF/PCEF (SA node) when PDP session hasbeen terminated in GGSN. If Session Stop Indicator is included in RADIUSaccounting STOP request, then SA node may know that PDP session isterminated in GGSN and the related NAS context may be terminated in SAnode.

Furthermore, the SA node may keeps track of all the Accounting SessionID values related to NAS context, i.e. all the Accounting Session IDvalues of all PDP contexts of the related PDP session. When RADIUSaccounting STOP request is received, SA node will remove the relatedAcct-Session-Id. If there are no Acct-Session-Ids linked to NAS contextafter this procedure, the SA nodes may start an IDLE Timer. If no userplane traffic is detected before IDLE Timer expiration, NAS context maybe terminated. However, if user plane traffic is detected before IDLETimer expires, then SA node may know that there are still active PDPcontexts in the PDP session even though SA node does not know therelated Acct-Session-Id.

Additionally, if SA node receives RADIUS INTERIM/STOP accounting requestand Accounting Session ID cannot be associated with NAS context, thenthe SA node may analyze the IP address, IMSI, MSISDN and APN values inthe RADIUS request. If matching NAS context can be found based on thesevalues, then the received Accounting Session ID can be linked to thefound NAS context and accounting request may be processed.

According to an additional exemplary aspect of the invention a method ofindicating a free resource in a communication network is provided,wherein the method comprises implementing an Accounting Stop Requestinto a RADIUS Accounting Stop Request, and transmitting the AccountingStop Request to a network access server of the communication network.

It has to be noted that embodiments and aspects of the invention havebeen described with reference to different subject-matters. Inparticular, some embodiments and aspects have been described withreference to apparatus type claims whereas other embodiments have beendescribed with reference to method type claims. However, a personskilled in the art will gather from the above and the followingdescription that, unless other notified, in addition to any combinationof features belonging to one type of subject-matter also any combinationbetween features relating to different subject-matters, in particularbetween features of the apparatus type claims and features of the methodtype claims is considered to be disclosed with this application.

The aspects and exemplary embodiments defined above and further aspectsof the invention are apparent from the example of embodiment to bedescribed hereinafter and are explained with reference to these examplesof embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a SA node in Gi deployment.

FIG. 2 schematically illustrates a flowchart of a method according to anexemplary embodiment of the invention.

DETAILED DESCRIPTION

The illustration in the drawing is schematic.

With reference to FIGS. 1 and 2 an embodiment of the present inventionwill be described in more detail.

As already mentioned above a Public Land Mobile Network (PLMN) 100 maycomprise a Service Aware (SA) node 101, such as the so-called Flexi ISN,which can be deployed behind a Gateway GPRS Support Node (GGSN) 102,corresponding to a so-called Gi-deployment, to enable operators to offerservices in a more flexible and efficient way. A mobile phone 103 may beused for transferring data or data packets in the PLMN network and maycommunicate with the GGSN which is indicated by arrow 104 in FIG. 1.

The communication between GGSN and SA node may be performed through theNetwork Access Server (NAS) interface. NAS interface uses RadiusAuthentication Dial In User Service (RADIUS) authentication forallocating the IP address (if needed) and RADIUS accounting forproviding the IP address, International Mobile Subscriber Identity(IMSI) and Mobile Subscriber ISDN (MSISDN) to the SA node. That is, theGGSN 102 as well as the SA 101 may comprise an interface adapted toperform the necessary communication for a RADIUS service. In FIG. 1 thecommunication relating to the RADIUS service is indicated by the arrow105. For example, the NAS interface can be formed a 3rd party GGSN thatacts as a RADIUS client and a SA node that acts as a RADIUS server. Theuser plane traffic is carried in plain IP, Generic Routing Encapsulation(GRE) or IP-in-IP tunnels which is indicated schematically by the pipe106 and the RADIUS signalling is used to set up the user plane trafficin a similar way as in the GPRS/3G networks. The NAS interface can bereferred to as being the southbound Gi interface, as an alternative tothe Gn interface.

FIG. 2 schematically illustrates a flowchart 200 of a method accordingto an exemplary embodiment of the invention.

When an “accounting request STOP” message is received 201, it is checkedif the Accounting Session ID matches any of the Accounting Session ID ofthe NAS Contexts 202.

1. If a match is found 203 then:

It is checked whether a Session Stop Indicator attribute is included204.

-   -   In case the Session Stop Indicator attribute is included 205 the        NAS Context is deactivated 206. The deactivation may also inform        external network nodes (Charging, RADIUS).    -   If the Session Stop Indicator attribute is not included 207 then        it is further checked whether the Accounting Session ID is the        last Accounting Session ID relating to the respective NAS        session or NAS context 208.    -   If this is the last Accounting Session ID of the NAS Context 209        then it is removed from the NAS context and an operator        configurable IDLE timer is started 210. After the IDLE timer        expires and no user plane traffic is received for that NAS        Context, the NAS context is disabled.    -   If this is not the last Accounting Session ID of the NAS context        211 then only the Accounting Session ID is removed from the NAS        Context 212.

2. If a match is not found 213 then:

It is checked whether an existing NAS context is found with sameFramed-IP-Address and/or same Called-Station-Id (APN) and/or sameCalling-Station-Id (MSISDN), and/or 3GPP-IMSI 214.

-   -   In case such a matching is found, i.e. an active NAS context is        found 215, it is checked whether a Session Stop Indicator        attribute is included 216.        -   If such a Session Stop Indicator attribute is found 217 the            NAS context is deactivated 218. The deactivation may also            inform external network nodes (Charging, RADIUS).        -   If the Session Stop Indicator attribute is not included 219            the received RADIUS message is ignored and the NAS context            is kept active 220.    -   If an existing NAS context is not found with same        Framed-IP-Address and/or same Called-Station-Id (APN) and/or        same Calling-Station-Id (MSISDN), and/or same 3GPP-IMSI 221 the        received RADIUS message is ignored 222.

It should be noted that the items stated under 1. may avoid any problemscaused when GGSN fails to include session STOP indicator when it shouldbe implemented, e.g. a RADIUS accounting STOP request, while the itemsstated under 2. may avoid dropping of data packets, since when using therespective method it may be possible that the SA node, e.g. a so-calledFlexi node, is informed that secondary PDP contexts may exist in GGSNbut not in the SA node.

Furthermore, it should be noted that IDLE timer defined here is not thesame idle timer, which may be used in general to terminate idle bearersessions in GGSN or SA node. Typical value for general idle timer can beseveral hours, while the IDLE timer used in this embodiment wouldtypically have configured value as only a few minutes. If user planetraffic is detected before IDLE timer expires then SA node knows thatthere is active (but yet unknown) PDP context related to NAS context andit may start using general idle timer to detect inactivity in the NAScontext. That is, the method according to an exemplary embodiment maycomprise two different timers, which may operate in parallel or inseries.

Even if usage of IDLE timer means that detection of the terminated PDPsession may happen later than it actually occurred, the SA node will usethe correct termination time when it is informing other nodes about theterminated NAS context. Event-Timestamp attribute can be used in RADIUSand Diameter requests originated from the SA node to indicate the righttime when the NAS context was terminated and Change Time informationelement in CDR will be used for same purpose in offline charginginterface.

Finally, it should be noted that the above-mentioned embodimentsillustrate rather then limit the invention, and that those skilled inthe art will be capable of designing many alternative embodimentswithout departing from the scope of the invention as defined by theappended claims. In the claims, any reference signs placed inparentheses shall not be construed as limiting the claims. The word“comprising” and “comprises”, and the like, does not exclude thepresence of elements or steps other than those listed in any claim orthe specification as a whole. The singular reference of an element doesnot exclude the plural reference of such elements and vice-versa. In adevice claim enumerating several means, several of these means may beembodied by one and the same item of software or hardware. The mere factthat certain measures are recited in mutually different dependent claimsdoes not indicate that a combination of these measures cannot be used toadvantage.

LIST OF REFERENCE SIGNS

-   100 PLMN-   101 SA node-   102 GGSN-   103 Mobile phone-   104 Arrow-   105 Generic Routing Encapsulation-   106 IP-in-IP tunnel-   200 Flowchart-   201 Accounting Request STOP-   202 Acct. Session ID match?-   203 Match found-   204 Session Stop Indicator included?-   205 Positive result-   206 Deactivate NAS context-   207 Negative result-   208 Last Acct. Session ID?-   209 Positive result-   210 Remove Acct. Session ID and start IDLE Timer-   211 Negative result-   212 Remove Acct. Session ID-   213 No match found-   214 IP, APN, MSISDN, IMSI match?-   215 Match found-   216 Session Stop Indicator included?-   217 Positive result-   218 Deactivate NAS context-   219 Negative result-   220 Ignore message-   221 Negative result-   222 Ignore message

1-13. (canceled)
 14. A method of locating NAS context relating to anetwork access server session in a communication network, the methodwhich comprises: receiving an Accounting Stop Request for a PDP contextassociated with a network access server session; comparing an AccountingSession ID implemented in the Accounting Stop Request with AccountingSession IDs associated with active network access server sessions; if nomatching Accounting Session ID is found, determining whether a value ofan identification parameter implemented in the received Accounting StopRequest matches a value of a corresponding identification parameterassociated with an active network access server session; and locating aNAS context based on the result of matching identification parameters.15. The method according to claim 14, wherein the identificationparameter is selected from the group consisting of an IP address, anAccess Point Name, an International Mobile Subscriber Identity, and aMobile Subscriber ISDN.
 16. The method according to claim 14, whereinthe located NAS context corresponds to the NAS context having a relatednetwork access server session to which a matching value of anidentification parameter is associated.
 17. The method according toclaim 16, which comprises deactivating the located NAS context if adetermination is made that a Session Stop Indicator is included in theAccounting Stop Request.
 18. The method according to claim 16, whichfurther comprises ignoring the Accounting Stop Request if adetermination is made that a Session Stop Indicator is not included inthe Accounting Stop Request.
 19. The method according to claim 14, whichfurther comprises, if no matching value of identification parameters isfound, ignoring the received Accounting Stop Request at a receivingside.
 20. The method according claim 14, which further comprises: if amatching Accounting Session ID is found, deciding whether or not aSession Stop Indicator is included in the Accounting Stop Request; if noSession Stop Indicator is included, deciding whether or not further PDPcontexts are associated with the network access server session; and ifno further PDP context is associated with the network access serversession, starting an IDLE Timer to determine a point in time forreleasing the communication resources.
 21. The method according to claim20, which comprises: determining the point in time based on apredetermined time interval; and measuring the predetermined timeinterval from the starting of the IDLE Timer.
 22. The method accordingto claim 20, which further comprises, if the IDLE Timer is started,checking whether or not further communication associated to the networkaccess server session is performed in the communication network.
 23. Themethod according to claim 22, which further comprises, if no furthercommunication is performed until the determined point in time isreached, deactivating the network access server session.
 24. The methodaccording to claim 20, which further comprises removing the AccountingSession ID from the network access server context associated with thenetwork access server session, in case no Accounting Session ID isincluded.
 25. A program element, comprising code, when being executed bya processor, is adapted to control or carry out the method according toclaim
 14. 26. A computer-readable medium, comprising computer-readableprogram code stored on the computer-readable medium which, when loadedinto and executed by a processor, is configured to control or carry outthe method according to claim 14.